Parameter & * diff

Noah L 1

131170-%E1%84%83%E1%85%AE%E1%86%AF%E1%84%8B%E1%85%B4-%E1%84%8E%E1%85%A1%E1%84%8B%E1%85%B5.png

void f1(int& a) {
a = 1;
}

void f2(int* a) {
*a = 2;
}

void main() {
int x = 0;
f1(x);
std::cout << x << std::endl;

f2(&x);  
std::cout << x << std::endl;

}

f1, f2가 결국 main함수의 x 데이터를 바꾸는 같은 동작을 하는데,

실제 둘의 차이는 뭘까요?

Barry Schwarz 2,511 Reputation points

2021-09-11T09:25:13.363+00:00

Translation: f1 and f2 end up changing the x data of the main function, doing the same thing, What's the real difference between the two?

For the simple case of a scalar such as int, the only practical difference is the need for the dereference operator (*) in f2.

If the argument is an array, using sizeof(a) in f1 would evaluate to the actual array size while in f2 it would evaluate to the size of a pointer. Even using sizeof(*a) in f2 will not return the array size.

If the argument is a class or struct, f1 must use the . operator to access a member while f2 must use the -> operator.
Noah L 1 Reputation point

2021-09-12T08:12:31.067+00:00

Thank you so much

1 answer

David Lowndes 4,711 Reputation points

2021-09-11T09:04:18.853+00:00

I think you're looking to understand the difference between a reference and a pointer.
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